Survivalist market

There are survivalists who would like a home that could have a good chance of surviving various potential disasters like breakdown of society, nuclear war, disease outbreaks, etc. A Single Family Seastead with a few extras should be able to serve this part of the seastead market.

Food

A seasteader could get their own food by fishing, hydroponics, and maybe aquaculture. A seastead should act as a Fish Aggregating Device so it will probably be easy to catch plenty of fish for one family. Watermakers are easy enough. A supply of hydroponics nutrients to last many years is not very large (most of the mass of food comes from water and the carbon in the air). Food storage food is also very reasonably priced and small enough to fit on a seastead.

Disease

A seastead could stay isolated from other human or animal contact to make it impossible for many types of contagious diseases to get to it.

Power

Solar panels can provide power for 25+ years. Costs are now down to around $2/watt. Could have a very small generator as a backup.

Propulsion

Solar would be enough power for electric thrusters if we use efficient propellers. Might also use a kite and sea-anchor. You can get a 500 lbs thruster that uses about 2,000 watts. If you only drove when the sun was up and used $2/watt panels, that is about $4,000 worth of solar panels. Probably you want batteries and several times that in solar panels.

Defense

A survivalist on a seastead out in the deep ocean sort of has a big moat around him making attack from hungry people trying to get the survivalists food less of a problem.

Market size

It is not clear how many survivalists would be interested in buying a seastead. This would depend on how much seasteads costs. But even a small market segment could help with initial sales of seasteads.